Pixy

Pixy is a fast vision sensor you can quickly “teach” to find objects, and it connects directly to Arduino and other controllers.
Pixy uses a hue-based color filtering algorithm to detect objects. Most of us are familiar with RGB (red, green, and blue) to represent colors. Pixy calculates the hue and saturation of each RGB pixel from the image sensor and uses these as the primary filtering parameters. The hue of an object remains largely unchanged with changes in lighting and exposure. Changes in lighting and exposure can have a frustrating effect on color filtering algorithms, causing them to break. Pixy’s filtering algorithm is robust when it comes to lighting and exposure changes and significantly better than previous versions of the CMUcam.